Vascularised endosteal bone tissue in armoured sauropod dinosaurs

• Autores: Chinsamy, Anusuya; Cerda, Ignacio Alejandro; Powell, Jaime E.
• Año de publicación: 2016
• Idioma: español castellano
• Tipo de recurso: artículo
• Materia: Ciencias Ambientales y de la Tierra; Paleohistilogy; Dinosauria; Pathology; Medullary Bone; Ciencias Ambientales y de la Tierra
• Institución: Universidad Nacional de Río Negro

Fil: Chinsamy, Anusuya. University of Cape Town; South Africa
Fil: Cerda, Ignacio A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina
Fil: Cerda, Ignacio A. Instituto de Investigación en Paleobiología y Geología; Argentina
Fil: Powell, Jaime E. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.
Fil: Powell, Jaime E. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina
The presence of well-vascularised, endosteal bone in the medullary region of long bones of nonavian dinosaurs has been invoked as being homologous to medullary bone, a specialised bone tissue formed during ovulation in birds. However, similar bone tissues can result as a pathological response in modern birds and in nonavian dinosaurs, and has also been reported in an immature nonavian dinosaur. Here we report on the occurrence of well-vascularised endosteally formed bone tissue in three skeletal elements of armoured titanosaur sauropods from the Upper Cretaceous of Argentina: i) within the medullary cavity of a metatarsal, ii) inside a pneumatic cavity of a posterior caudal vertebra, iii) in intra-trabecular spaces in an osteoderm. We show that considering the criteria of location, origin (or development), and histology, these endosteally derived tissues in the saltasaurine titanosaurs could be described as either medullary bone or pathological bone. Furthermore, we show that similar endosteally formed well-vascularised bone tissue is fairly widely distributed among nondinosaurian Archosauriformes, and are not restricted to long bones, but can occur in the axial, and dermal skeleton. We propose that independent evidence is required to verify whether vascularised endosteal bone tissues in extinct archosaurs are pathological or reproductive in nature.